These are useful to provide examples in code. Often, with jOOQ, it is even more useful to compare SQL code with its corresponding Java/jOOQ code. When this is done, the blocks are aligned side-by-side, with SQL usually being on the left, and Java usually being on the right:

The contents of code blocks follow conventions, too. If nothing else is mentioned next to any given code block, then the following can be assumed:

-- SQL assumptions
------------------
-- If nothing else is specified, assume that the Oracle syntax is used
SELECT 1 FROM DUAL

// Java assumptions
// ----------------
// Whenever you see "standalone functions", assume they were static imported from org.jooq.impl.Factory
exists(); max(); min(); val(); inline(); // correspond to Factory.exists(); Factory.max(); Factory.min(); etc...
// Whenever you see BOOK/Book, AUTHOR/Author and similar entities, assume they were (static) imported from the generated schema
BOOK.TITLE, AUTHOR.LAST_NAME // correspond to com.example.generated.Tables.BOOK.TITLE, com.example.generated.Tables.BOOK.TITLE
FK_BOOK_AUTHOR // corresponds to com.example.generated.Keys.FK_BOOK_AUTHOR
// Whenever you see "create" being used in Java code, assume that this is an instance of org.jooq.impl.Factory:
Factory create = new Factory(connection, SQLDialect.ORACLE);